U.S. Pat. No. 5,210,664 Perona shows a drive for the mini data cartridge containing magnetic tape which stores computer data. Small tape drives for writing and reading data stored on 1/4" tape in these mini cartridges are commonly used in personal computer systems.
U.S. Pat. No. 5,268,802 Bar--Reading Non-Standard Tapes on Tape Drives relates to drives which read tape in the QIC format, and which also read tapes written in another, non-standard, format.
Quarter-Inch Cartridge Drive Standards Inc. 311 East Carillo Street, Santa Barbara, Calif. 93101 publishes development standards adopted by several manufacturers for this type of tape drive.
QIC-3020-MC Revision G, Sep. 1, 1995 SERIAL RECORDED MAGNETIC TAPE MINI CARTRIDGE FOR INFORMATION INTERCHANGE contains the development standard for a tape drive which writes and reads tapes referred to as Travan, in this case, Travan III or TR3. Using these tape cartridges, the drive is capable of recording 1.6 GB of data.
It is an object of the present invention to provide a magnetic tape drive, and a magnetic tape format in which an increased amount of data, for example 2.5 GB, can be recorded in a cartridge having the same physical characteristics. The tape drive of the present invention must distinguish between cartridges formatted in the new, high density format, and the standard, lower density format. This distinction cannot be made based on the physical characteristics of the cartridge as has usually been done in common practice. Also, the distinction cannot be made reliably based on the frequency of reference bursts and the distance between them, as in the QIC3020 drives. Because the physical characteristics of the cartridges are the same, and the frequency of the bursts is the same, and distance between bursts is close, the formats must be uniquely distinguished by the drive to prevent a tape recorded in the new, high density format from being written on by a drive which does not have the capability for operating in the high density format. Otherwise, important data on the high density tape may be lost. A tape formatted with the high density format may be ruined.